Fire investigators believe an early-morning fire in a multi-family home on the city’s north side was set on purpose.

Firefighters responded to the blaze at 128 Avenue and 121 Street at about 1:30 a.m. Tuesday.

Crews arrived to find the fourplex completely engulfed in flames.

The two-alarm blaze was declared out by 6 a.m.

Residents living near the scene said the heat and the noise woke them up.

“I thought ‘That isn’t lightning’, so I opened by curtains,” Patricia Woldemichael said. “All I see is orange, a wall of orange.”

“It was like a roar, a crackling roar,” Dayna Mitchell said. “I heard it inside my house, the dog was terrified.”

While the fire is still under investigation by police, later in the day investigators said it caused about $660,000 in damages.

Nearby houses were saved from the flames, except for part of a nearby duplex - however some others were damaged by the heat.

No injuries were reported.

With files from Serena Mah